The light emitting diodes are widely used as the light sources in large screen color display systems, automotive lightening, traffic lights, multimedia displays, optical communication systems, and so on. Since the brightness of light emitting diode is limited, the light emitting diodes cannot be applied to indoor lighting on a large scale. So it is necessary to increase the luminous efficiency of light emitting diodes. However, the refractive index of the semiconductor materials is high, only a small part of light generated by the light emitting diodes can radiate into the outside, and most of the light is absorbed by the electrode or the light-emitting layer. Therefore, the luminous efficiency of light emitting diodes is lower.
What is needed, therefore, is to provide a light emitting diode for solving the problem discussed above.